Amazon has recently released Photo Studio feature in their Amazon seller App. It looks good and allows you to do a minor retouch on photo including cropping. Worth a try!
Additionally, it tells us whether the photo meets Amazon’s photo requirements as listed below:
• MAIN images must have a pure white background
• MAIN images must be the actual product
• Images should be 1,000 pixels or larger in either height or width. This minimum size requirement enables the zoom function on the website. Zoom has been proven to enhance sales. The smallest your file can be is 500 pixels on its longest side
• Logos, watermarks or texts are now allowed